The invention relates to apparatus for filling a toner particle supply reservoir from which toner is withdrawn for use in a non-mechanical printer or copier machiner developer station.
According to electrophotographic principles typically utilized in non-mechanical copying or printing machines, electrostatic charge images of characters to be printed are generated on a recording medium, such as a photoconductive drum or specially treated paper. These charge images are subsequently inked with a print powder, called toner particles and which is typically black, in a developer station. The developer station typically includes at least one developer unit generally referred to in the art as a magnetic brush developer. A magnetic brush developer, as a rule, utilizes a two-component magnetizable developer mix for developing the latent charge images recorded on the recording medium. The two components of the developer mix consist of ferromagnetic carrier particles and toner powder particles. The magnetic brush arrangement serves to conduct developer mix particles passed the charge images formed on the recording medium, whereupon the toner adheres to the charge images as a result of electrostatic forces. Electrophotographic principles are conventionally known. One such electrophotographic copying machine construction is disclosed, for example, in U.S. Pat. Nos. 3,784,297 and 3,883,240.
As a result of the process whereby charge images are inked in the developer station, the concentration of toner particles within the developer mix, i.e., the percentage of toner particles relative to carrier particles is constantly decreasing in the developer as the toner is used up. It is, therefore, necessary to constantly or frequently supply new toner to the developer mix. Typically, this replenishment of the toner supply is carried out in metered fashion. Since the rate of consumption of toner is very high in fast copying machines and high-performance data printers, a spacious toner reservoir is typically employed in connection with the developer stations in order to avoid downtime during the resupplying of toner. When this toner reservoir is empty, it is typically re-filled from handy containers or bags containing toner particles. This re-filling step is carried out manually and it is necessary, since spilled toner can be messy and can interfere with the copier or printer machinery, to carry out this step in a manner which substantially precludes loose toner particles from ending up outside of the reservoir.
An object of the present invention is to provide a toner re-filling apparatus whereby the re-supply of toner particles is assured to pass only into the reservoir, such that messy spillage or machinery contamination with toner about the reservoir is no longer possible.